The therapeutic effect of promoting drainage from wound cavities is well known and there are conventional devices designed to promote such drainage. These devices which afford a route of exit or discharge from a wound cavity have come in various forms and can be classified generally in three groups.
The first group employs a hollow structure, such as a tube, which is placed in the wound to allow the removal of wound discharge by, e.g., capillary action and/or siphonage and/or gravity. A number of these "tube" type drains have also been used in conjunction with vacuum producing apparatus to assist drainage. Features shared by tube-type surgical drains include 1) ease of insertion into a wound cavity and 2) their drainage function is not generally affected by the volume of discharge. Further, since they provide constant drainage, the need to replace them is significantly reduced. There are, however, a number of disadvantages of tube-type surgical drains, including, the difficulties of avoiding infection and promoting healing inherent in a device inserted in a wound cavity that is nondegradable. Tube-type surgical drains can also be uncomfortable for the patient because of their stiffness, lack of flexibility, and relatively large diameter. In addition, tube-type surgical drains may be prone to blockage and other forms of obstruction, e.g., when the tube opening contacts body tissue the passage of discharge may be obstructed.
The second group of surgical drain devices includes those made of various forms of fibers and fabrics having absorptive properties which are placed in a wound cavity to allow removal of wound discharges, e.g., by absorption. Features shared by these "fabric" type surgical drains are that they can be relatively easily sized and manipulated regardless of the size of the wound cavity and may be less prone to blockage or obstruction than tube-type drains. As with tube-type drains, fabric-type drains suffer from a number of disadvantages, such as susceptibility to sluffing or linting, which may promote irritation and associated infection, and their drainage capacity may be limited to the fluid retention capacity of the fabric, i.e., the drainage is not continuous. Drainage capacity problems may be aggravated by using hydrophilic fibers, e.g., cellulose yarns, due to their water binding properties. A consequence of the drainage capacity limitation is that fabric-type surgical drains must ordinarily be replaced at relatively short intervals.
Further, conventional fabric-type drain materials are often so loosely woven that they fragment which increases the risk of infection. Natural fibers like cotton, and other cellulosics, are themselves prone to sluffing small fragments that also increase the risk of infection. Depending on the fibers selected, known fabric-type surgical drains may decompose over time, again necessitating more frequent replacement, and, not uncommonly, debriding of the wound cavity. Known fabric-type surgical may also be difficult to relocate or retrieve. Another disadvantage of fabric-type drain materials is that they often do not remove particulates from the wound cavity.
The third group of surgical drain devices is a hybrid of the above described tube-type and fabric-type drains including both a hollow structure and absorptive fibers. In these combination-type surgical drains, a fabric is usually either wrapped around or arranged within a hollow structure to form a composite structure which may be inserted into a wound. Combination-type drains share some of the advantageous features of both tube-type and fabric-type drains. A disadvantage of these combination-type surgical drains is that they may not effectively remove particulates from a wound cavity.
An example of a combination-type drain routinely used in surgical procedures is made from gauze, e.g., a loosely woven cotton fabric, which may be layered, cut to size, shaped, and then placed in either surgical sheathing or a tubular part (finger) cut from a rubber glove prior to insertion into a wound cavity. The surgical sheathing or rubber glove part is used to prevent loose fragments or threads of the gauze from entering the wound cavity. Gauze is prone to fragmenting and leaves many loose threads when it is cut. Additional fragments of gauze may fall away under minimal pressure, i.e., slurring and linting. The use of the sheath or glove to limit such sluffing and linting however, is not completely effective or convenient for use in an operating room setting. Furthermore, drainage with this type of surgical drain may be limited to the fluid retention capacity of the fabric and a small amount of evaporation.
Other known surgical drains, include "cigarette drains," made by surrounding a strip of gauze with a protective covering of rubber, gutta-percha, or the like; and "Mikulicz" drains formed by pushing a single layer of gauze into a wound cavity, the layer of gauze being packed with several thick wicks of gauze as it is pushed into the cavity. These drains also suffer from disadvantages including susceptibility to sluffing or linting, and that their drainage capacity may be limited to the fluid retention capacity of the fabric.
U.S. Pat. No. 3,957,054, issued to McFarlane, describes a tube-type drain which is flexible and pliable and comprises a plurality of ribs arranged in such a fashion about the interior of the column of the tube so that the tube cannot be collapsed.
U.S. Pat. No. 4,139,012, and its related continuation application, now U.S. Pat. No. 4,217,904, both issued to Zahorsky, describe surgical drain tubes having a construction said to minimize the problem of clogging found in known tube designs via a protective shield member.
Other known surgical drains are described in U.S. Pat. Nos. 4,257,422; 4,551,141; 4,623,329; 4,315,509; 4,579,555; 4,080,970; 4,781,678; 4,692,153; 4,523,920; 4,654,032; 4,508,533; 4,856,299; and 4,815,299.
A need exists, therefore, for a relatively inexpensive and easily manufactured surgical drain capable of providing improved drainage and other advantageous properties without some of the disadvantages of known surgical drains such as clogging, sluffing, linting, slow drainage, non-continuous drainage, inability to remove particulates, and inability to provide a conduit for administering medication directly to the site, and decomposition. Similarly, a desirable surgical drain fabric would provide improved continuous drainage properties for extended periods that is not limited to the fluid retention capacity of the fabric or evaporation time.